| 摘要 |
PROBLEM TO BE SOLVED: To provide a focal-position detecting apparatus, whose constitution and adjustment are simple by which a focusing direction can be determined instantaneously and by which a focusing position can be detected quickly. SOLUTION: In this focus detecting apparatus, the face to be measured of an object 22 to be measured is irradiated with a measuring light from a semiconductor laser 29, and reflected light from the face to be measured is condensed. The reflected light, which is condensed by this optical system, is detected by an image pickup element 30, and a signal from the image pickup element 30 is processed by a signal processing part 33. In addition, astigmatism is generated by the optical system in the image of the reflected light on the image pickup element 30. Then, on the basis of the noncircularity of the image of the reflected light, the focusing position of the face to be measured is detected. |
